Buffing wheel



J. F. A. DAVIS BUFFING WHEEL Aug. 9, 1932.

Filed Oct. 20, 1927 Paten-red Aug. 9, 1932 UNITED STATES JOHN F. A.DAvIs, or WENHAM, MASSACHUSETTS IBUFFING WHEEL Application filed October20, 1927'. Serial No. 227,442. .Y

The invention relates to an improvement in buiiing wheels of that typein which the wheel is provided with a removable covering of someabrasive material wrapped 6 around the wheel and the ends of which arebrought together, retained and the covering tightened by mechanismwithin the wheel.

The object of the invention is to provide improved mechanism inside thewheel for gripping and holding the ends of the abrasive covering, andespecially a mechanism which will permit of the ends of the coveringbeing drawn inwardly by the gripping mechanism after it has gripped theends of the d' 15 covering in order that the covering may then be pulledproperly tight about the wheel.

The invention can best be understood by reference to the drawing inwhich- Figure 1 is a side elevation of the buiiing wheel embodying theinvent-ion, such portion only of the wheel being shown as is necessaryfor a proper understanding thereof.

Fig. 2 is also a. side elevation of certain portions of the wheel.

' 25 `l? ig. 3 is a cross section of the wheel, and

F ig. 4 is a plan of the interior or working side of the cam, to whichreference will later be made.

Referring to the drawing 1 represents the wheel of which `.2,is its rimand 3 its body. The body is preferably made dished excepting for adiametric portion 4 of a thickness substantially equal to the width ofthe rim.

w Wrapped around the rim of the wheel is a felt or cushion 5 and overthis is laid aniabrasive covering 6. This covering consists of a stripofsandpaper or other abrasive material in sheet form. In width itcorresponds with the width of the rim but in length is longer than thecircumference of 'the wheel with added feltY cushion to permit of itsends 77 7 passing through the cushion, thence through a radial slot 8cut in the rim and A into .a chamber 9 within which the ends ofthe stripare gripped and held and the Strip tightened on 4the wheel in a mannerlater to be explained. l

`The chamber 9 contains the gripping mechanism for the ends of. theabrasive Strip.

It is formed in the body portion 4 of the wheel adjacent the radial slot8 in the rim. This chamber is normally closed by a cover 10 secured tothe body portion t by screws l1 or in any other suitable manner.

The Wheel is provided with an axial opening 12. Outside this opening acircular opening or cavity 13z is formedV in the side of the bodyportion t. rlfhis opening is centrally located and the wall of thevbodyporl tion 4 surrounding the opening provides a central bearing for arotary cam later to be referred to.

The gripping mechanism for the ends of the abrasive strip larranged inthe chamber 9 comprises opposing jaws 15, 15. These jaws are pivotallyretained by a pin 16 passed through the Shanks of the respective jawsand through the clef end .of a slide bar 17 on which the jaw-s are thuspivotally arranged to turn. The jaws are held in a normal open positionout of engagement with the ends of the abrasive strip by means of aspring 18 common to both, this spring being passed laround the pin 16outside the end 75 of the bar 17 and connecting'withthe respective jaws.v

The bar 17 is arranged to slide in a radialk Slot or way 19 formedVwithin the body portion 4 of the wheel, the inner end of the bar 80entering the cavity 13 formed in the side thereof as aforesai l.Thusarrang-ed the'bar is movable in a radial direction with either aforward or reverse movement carrying with it the jaws 15, 15 of thegrip.8"

Socketed within the cavity 13 in the body portion i of the wheel is acam 2O having a spiral groove 21 cut in its inner side. EX- tending intothis groove is a cam member 22 projecting from the outer side of thesliding bar 17, the arrangement being such that as the cam is turned inone 'direction or the other it will operate through the cam member 22and sliding bar 17 to move the jaws 15, 15 of the gripl inwardly oroutwardly 95 within the chamber 9 in which they are contained.

The cam 2O is held in place by the iianged head 28 of a hub 24: whichlines the axial opening 12 through the centre of the wheel. 100

The hub 24 is secured by screws 25 which fasten partly into the endthereof and partly into the body portion et oi" the wheel which o thesprings extend upwardly with an inward inclination bearing against theunder sices of `the respective jaws, the bearing ends ot the springsbeing retained by means et pins 29 projecting from the under sides ofthe jaws and extending into the coils ot the springs. The relativearrangement of the springs 27 is such that as the slide bar i7 is movedinwardly by the operation of the cam, drawing the Yjaws of the grip withit,

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the laws will be drawn to engage the s Jrinrfs O C? C l27, distortingthem and causing them to exert pressure for closing the jaws andmaintaining. them in a closed position as long as the springs remaintensioned. V

The general operation is as follows: It

l will first be assumed that the aws l5, i5 of the grip have been movedoutwardly within the chamber 9 in which they are contained by theturning of4 the cam so that the springs 27 are nolonger active and thejaws are made to occupy their normal open position by the tension of thespring 18. rllhe ends 7', 7 of the abrasive covering or strip 6 are thenbrought together and passed through the slot 8 in the rim of the wheel,thence down into the chamber 9 orn the wheel and between the open jawsof the grip. The cam is new turned in a direction for drawing in thejaws of the grip, this action being consequent upon the drawing in ofthe slide bar 17 by the cam as explained above. As the operation of thecam is continued the jaws oit' the grip will be brought to bear againstthe springs 27 compressing them and the springs being thus. distortedwill exert pressure against the 'aws of the 0rin closin theni b 2D ALupon the ends 7, 7 ot' the abrasion strip. After the closing of the jawsupon the ends of the strip the operation of the cam is continued toeiiect a further inward movement Vor drawing in of the grip. inasmuch asthe jaws of the grip are then closed Vu pon tlie ends of the abrasivestrip, consequently the ends of the strip will be drawn or pulled in bythe grip tightening the abrasive strip on the wheel, the operation etthe cam being continued until the ends et the abrasive strip have beendrawn in so Jfar as to have made the ystrip to tightly hug the wheel orfelt covering. The action of the grip tending to draw in theends of thestrip after its jaws have closed upon said ends is permitted by thetensional means or springs which operate to close the aws. After thesesprings have effected a closure el the jaws upon the ends o'l' theabrasive strip a further inward movement of vthe grip is permitted fromthe tact that the springs which have closed the jaws and are maintainingthem in a closed position may still be further compressed,

" such action tending not onlyv to exert a urther tightening action uponthe jaws, but morer essentially permitting of such a turther inwardmovement of the aws or grip hem in engagement with the ends of theabrasive strip as will properly tighten the stripl around the wheel. f

A reverse movement of the cam permits a release of the abrasive strip,the jaws of the grip lirst being moved outwardly loosening the strip, a'further continued movement of the cam operating to move the jaws out sofar that the springs 2'? are no longer effective for closing the awswhen the jaws will be allowed to open releasing the ends of the abrasivestrip which may then be removed tor the pur ose of renewal.

Having t us fully described my invention,

'l claim and desire to secure'by Letters of the carrier, means forpivotally securing the opposing jaws of the grip to the grip carrierwhereby as the grip is moved inwardly both jaws may be moved laterallytoward one an.- other into engagement with said ends of the abrasivesheet and grip the sheet between them on bringing the jaws together,springs backing said jaws of the grip and arranged interposed7respectively, between said jaws and the bottom of said chamber withinwhich the grip Vis contained whereby the springs will be tensioned bydraft of the jaws as the aws are moved inwardly by the carrier as.aforesaid and thereby exert force to close the jaws for gripping themeeting ends of the abrasive sheet as aforesaid, and whereby also inwardmovement of the jaws and tensioning of the springs may becontinued'after the aws have gripped said ends of the abrasive sheet asaforesaid, and means for moving the grip carrier inwardly or outwardly.

2. A bufiing wheel comprising the body of the wheel having within it achamber open for receiving the'meeting ends of an abrasive covering forthe wheel, a grip having opposing jaws located within said chamber,aninwardly and outwardly movable grip carrier, means for `pivotallysecuring the opposing jaws of the grip to the` grip carrier whereby asthe grip is moved inwardly both jaws may be moved laterally toward oneanother into engagement with said ends of the abrasive sheet and gripthe sheet between them on bringing the jaws together, a springengagement at least one of said jaws for holding them apart when thegrip carrier is moved to its outward position, springs backing said jawsof the grip and arranged interposed, respectively, between said jaws andthe bottom of said chamber within which the grip is contained wherebythe springs will be tensioned by draft of the jaws as the jaws are movedinwardly by the carrier as aforesaid and thereby exert force to closethe jaws for gripping the meeting ends of the abrasive sheet asaforesaid, and whereby also inward movement of the jaws and tensioningof the springs may be continued after the jaws have gripped said ends ofthe abrasive sheet as aforesaid, and means for moving the grip carrierinwardly or outwardly.

JOHN F. A. DAVIS.

